Radio frequency discharge waveguide laser technology development by us has included 10.6.mu. (micron) wavelength C0.sub.2 (carbon dioxide) gas, 2.7.mu. wavelength HF (hydrogen fluoride) gas, 3.8.mu. DF (deuterium fluoride) gas lasers. A maximum electrical efficiency of 5.3% and 4.0% for pulsed HF and DF gas chemical lasers, respectively, was demonstrated at a low repetition rate of 100 Hz. As the repetition rate increased, the efficiencies were decreased. Since the waveguide configuration utilizes longitudinal gas flow, the flow velocity is restricted by the small cross section of the waveguide bore; and, therefore, the gas replenishment rate in the waveguide is low.
For the CW (continuous wave) C0.sub.2 laser, the advantage of the waveguide configuration is that it operates in a high pressure range of 50 to 150 torr to provide a broad frequency tunability. It has, however, a limited heat transfer capability which limits the maximum power loading per unit volume and the power output per unit value length. The typical gain is 0.3-0.6 watts per centimeter. It is suitable for a 1-10 watt laser with 10-50 cm gain length. For some applications requiring a C0.sub.2 laser with power higher than 50 watts, such a waveguide laser would have a rather long gain length, normally longer than one meter.